DATABASE REGISTRATION SOURCE DEVICE, REGISTRATION DESTINATION DEVICE, AND DATABASE SYNCHRONIZING DEVICE

摘要

PROBLEM TO BE SOLVED: To shorten the time required to synchronize contents of databases on plural devices in case of a communication fault with respect to a database synchronizing device which equalize the contents of databases on plural devices connected by a communication line. SOLUTION: A registration source device 1 sends a command number and the contents of a change as a command to a registration destination device 2 if its database item changes and stores the number and contents of the sent command as a sent command and the registration destination device 2 analyzes the command sent from the registration source device 1, changes its database item, and stores the number of the received command as a received command number. The registration destination device 2 sends a final reception command number to the registration source device 1 after a commination fault recovers and the registration source device 1 compares the number of the final transmission command with the final reception command number and sends commands from the command number right after the final reception command number to the number of the final transmission command to synchronize the databases.